Why it's included Included for its role in supporting fat metabolism and energy production
The pivotal mouse study used subcutaneous injection, not oral dosing a real mismatch between the tested route and typical community/commercial use
Chronic intestinal infections: Bacterial or parasitic infections that persist over a long period damage the gut lining and impair absorption of multiple nutrients, with B12 among the most commonly affected
translation to another tissue, species, or route of exposure
For example, if your Hb is low, and your MCV is raised, and then put on B12, and the Hb rises and MCV falls, there's the answer
Methylcobalamin is more bioavailable than its synthetic counterpart, cyanocobalamin, and therefore more effective because it is absorbed more readily by the body